Clefs at key signature step of score creation

Inspired by this and some discussions about the user having a reference for key signatures, could we have a large-ish treble clef on the left and the 15 key signatures on the right (5 horizontally and 3 vertically) in the key signature step during score creation?

Both would fit inside a rectangle shape and the clef could be changeable using 'Up'/'Down' buttons with the key signatures also changing to reflecting this.

I'm not quite sure about the palette - any suggestions?

What do others think?